C# OData的更新和删除操作

在C#中，使用OData（Open Data Protocol）可以轻松地处理来自Web API的数据

1. 引入必要的命名空间：

using System; using System.Net.Http; using System.Web.Http; using System.Linq; using Newtonsoft.Json.Linq; 

2. 配置Web API以支持OData：

public static class WebApiConfig {     public static void Register(HttpConfiguration config)     {         // Enable OData         config.MapHttpAttributeRoutes();          config.Routes.MapODataRoute(             name: "odata",             routePrefix: "api",             defaultQueryOptions: new ODataQueryOptions<MyEntity>(),             routingConventions: new[] { new QueryPathRoutingConvention() }         );     } } 

3. 创建一个实体类（例如MyEntity）：

public class MyEntity {     public int Id { get; set; }     public string Name { get; set; } } 

4. 创建一个继承自ODataController的控制器：

public class MyEntitiesController : ODataController {     private static readonly HttpClient client = new HttpClient();      // GET api/myentities     [EnableQuery]     public IQueryable<MyEntity> Get()     {         return client.GetAsync("https://api.example.com/data").Result.Content.ReadAsAsync<IQueryable<MyEntity>>();     }      // GET api/myentities(5)     [EnableQuery]     public SingleResult<MyEntity> Get(int key)     {         return client.GetAsync($"https://api.example.com/data/{key}").Result.Content.ReadAsAsync<SingleResult<MyEntity>>();     }      // POST api/myentities     [HttpPost]     public HttpResponseMessage Post([FromBody] MyEntity entity)     {         var newEntity = entity;         newEntity.Id = 1; // Assign a unique ID         return Request.CreateResponse(HttpStatusCode.Created, newEntity);     }      // PUT api/myentities(5)     [HttpPut]     public HttpResponseMessage Put(int key, [FromBody] MyEntity entity)     {         var existingEntity = client.GetAsync($"https://api.example.com/data/{key}").Result.Content.ReadAsAsync<MyEntity>();         if (existingEntity != null)         {             existingEntity.Name = entity.Name;             return Request.CreateResponse(HttpStatusCode.NoContent);         }         else         {             return Request.CreateResponse(HttpStatusCode.NotFound);         }     }      // DELETE api/myentities(5)     [HttpDelete]     public HttpResponseMessage Delete(int key)     {         var existingEntity = client.GetAsync($"https://api.example.com/data/{key}").Result.Content.ReadAsAsync<MyEntity>();         if (existingEntity != null)         {             client.DeleteAsync($"https://api.example.com/data/{key}");             return Request.CreateResponse(HttpStatusCode.NoContent);         }         else         {             return Request.CreateResponse(HttpStatusCode.NotFound);         }     } } 

现在，您已经实现了基本的更新和删除操作。请注意，这个示例使用了HttpClient来与Web API进行通信，您可以根据需要替换为其他HTTP客户端库。